Solid plates of titanium and zirconium



March 12, 1.957

SOLID PLATES Filed June '7, 1955 F13. Ian.

R. S. DEAN OF TITANIUM AND ZIRCONIUM 5 Sheets-Sheet l March 12, 1957 R. s. DEAN 2,785,066

SOLID PLATES 0F TITANIUM AND ZIRCONIUM Filed June 7, 1955 5 Sheets-Sheet 2 y/A. Fig.1

March 12, 1957 R. s. DEAN SOLID PLATES OF TITANIUM AND ZIRCONIUM 5 Sheets-Sheet 3 Filed June 7, 1955 III,

March 12, 1957 R. s. DEAN 2,785,066

SOLID PLATES OF TITANIUM AND ZIRCONIUM Filed June '7, 1955 5 Sheets-Sheet 4 5 /7 39 /6 I lab m 0 o o 3/ 22 an. 2/ i 630 I o o o 0 March 12, 1957 R. s. DEAN SOLID PLATES OF TITANIUM AND ZIRCONIUM 5 Sheets-Sheet 5 Filed June '7, 1955 .alloyin g.

znsspss soLm PLATES or TITANP-UM AND ZmcoNnIM Reginaid S. Dean, Hyattsvilie, Md msignor to Chicago Development Corporation, Riverdaie, Md.

Application dune 7, 1955, Serial N 513,759

3 Claims. (Ci. 75-1755) This invention relates to a new form of titanium and zirconium which is particularly suitable for melting and In the known art, titanium and zirconium have been produced in either spongy or particulate form.

The present invention has for its object the production of an entirely new form or" titanium and zirconium. This form consists of solid plates. By this descriptionl mean to identity the metal in relatively smooth, often nearly fiat, and relatively thin pieces, marked by density or compactness and of uniform coherent texture. By texture in this definition I mean to designate the disposition or manner of union of the particles. The article of my invention is thus clearly distinguished from the spongy masses produced by the Kroll process, or by electrolytic processes, such as that of British Patent 682,919, November 19, 1952 now U. S. Patent 2,553,586. I wish also to distinguish from filiform aggregates such as those produced by sodium reduction of titanium tetrachloride. I likewise propose to distinguish the article of my invention from dendritic crystalline material, which may to some extent accompany the spongy products of the known art. The articles of my invention are illustrated in Figures la, laa, lb, 1c, 1e, 1i and ljj. In Figure 1a is shown a group of plates, separated from the cathode, such as may be produced in accordance with Example I. Figure laa shows a microscopic cross-section of suchaplate, which has been polished and etched to reveal the structure. In Figure 1b is shown a tabular plate such as produced by Example H. In Figure 1c is shown an aggregate of plates and crystals produced according to Example VI. Figure 12 shows the curled plates made in accordance with Example ii. For the sake of comparison, Figure 1 shows sponge made in accordance with British Patent 682,919. Figure 1h shows particulate titanium made in accordance with my co-pending application Serial No. 488,540, filed Feb. 16, 1955. Figure 1i shows filiform titanium aggregates made by sodium reduction according to that application. Figure 1 shows a plate of alloy made in accordance with Example Ill. Figure 1 if shows the microstructure of such a plate. The

alpha beta structure is apparent.

In my co-pending application, Serial No. 488,540, filed February 16, 1955, I have disclosed methods of producing pure particulate titanium at the cathode of an electrolytic cell. I have also disclosed methods of producing metal objects such as steel coated with a thin layer of titanium or zirconium. T he article of my preesnt invention consists of plates easily separated from any metal on which they are formed and having sufficient thickness and integrity to form separate plates up to inch or more in thickness and several inches in the other dimensions. The product of my invention may be tabular in habit, that is, built up or" a number of thin plates. It may also consist of alternate layers of plates and crystalline material. It is, of course, intended that the plates of my invention are virgin metal, that is, they consist of metal produced for the first time from com- United States rates:

pounds of titanium and not from other forms of titanium by mechanical Work. My invention is thus clearly dis tinguished from plates which might be formed by rolling or hammering titanium sponge particles or melted ma terial.

The methods of producing the plates of my present in'= vention are within the scope of my co-pending applica-' tion. To produce the plates, however, I establish cer tain specific conditions. In the most general terms these conditions may be defined as the metasomatic replacement of a titanium-alkalinous metal alloy on a surface by titanium metal. The same thing holds for zirconium; metal, and to avoid repetition I wish it to be assumed in the further discussion that by titanium metal I mean also to include zirconium metal. I prefer to accomplish this by electrolytically depositing a layer of barium-titanium alloy, then replacing the barium in the layer with titanium by reacting with titanium 'trichloride. This reaction pro duces also titanium dichloride, which latter, in a suitable electrolyte containing barium, deposits a second layer of titanium barium alloy which undergoes another cycle of replacement. Particular means for accomplishing this process will be illustrated by examples to be given later.

It will be evident that the product of my invention will be substantially free from the alkalinous metal co-deposited with it provided there is a suitable relationship between the plating and replacing cycles. This situation may be controlled by adding chlorine near the cathode at a rate which is in proper relation to the current density. It may also be controlled by using a fluctuating or intermittent current so that each plating cycle is followed by a cycle of complete replacement.

For many purposes the presence of minor amounts of alkalinous metal in the plates of my invention is not objectionable, in fact, it may be advantageous for the preparation of certain alloys and to decrease the voltage in arc melting. Plates containing up to 1% of alkalinous metal are within the scope of my invention. They may be prepared by continuously plating with suitable chlorine additions.

In general I prefer to produce a product consisting entirely of plates. However, under certain conditions the plates may be produced intermingled or Stratified with particulate titanium. Such a product is within the scope of my invention which includes titanium partly or wholly made up of plates.

It is characteristic of the plates of my invention that they are very soft and ductile when formed in a molten salt bath. They may, therefore, occur in curved form or even as crinkled aggregates of platelets.

My invention provides for the first time a solid form of titanium which can be readily separated from the electrolyte by mechanical means, and which may be directly melted and alloyed to produce metal of excellent properties. When barium or strontium is used in the electrolyte, as I prefer, titanium or titanium alloys can be produced from the plates without vacuum melting which are of excellent properties, the trace of barium or strontium remaining after melting serving to bind the oxygen. This binding is enhanced by quenching the metal or alloys from 800 C. or thereabouts. It should be'pointed out that my process in one of its more important embodiments is a refining process.

In my co-pencing application, referred to above, I have disclosed the necessary conditions for refining titanium or zirconium in a cell of the kind illustrated. These conditions ar the maintenance of an open circuit voltage of less the ditierence between theeiectrode potential oftitanium and the least noble of the metallic impurities which are to be ieft in the anode residue. If the titanium to be refined contains only iron, then an open circuit voltage of 0.4 can be tolerated. 0n the other hand, if chroma a a 3 ilnn is present, the open circuit voltage of the refining 'cell rnust not be more than .15 volt. The open circuit voltage is determined by the rate of chlorine addition, and the current density as fully set forth in my copending application. V g

It should be pointed out that these data for refining at the anode presuppose operation at a temperature of uniform beta solid solution. As is well known, alloys of chromium, iron and manganese are not soluble in alpha titanium so that if the operation is carried out below the eutectoid temperature the anode will consist of alpha titanium and a compound as TiCra TiFez and Tilt/Ins. These compounds are not attacked at the anode and erely appear in the anode residue as such.

For complete anodic refining it is necessary that the voltage of the anode against pure .Ti'should be substantially zero. This can be conveniently determined by an auxiliary electrode in accordance with my copending application Serial No. 470,610, filed November 23, 1954. This condition cannot be maintained if Ba-Ti, or their equivalent, alloys are deposited at the cathode even on one phase of each cycle. If it is desired to operate a refining cell with the production of plate in accordance with this invention, 1 make use of a foraminous voltage divider in accordance with my co-pending application Serial No. 470,6l0, filed November 23, 1954.

It is to be pointed out, however, that this applies to refining when metals like Cr and Mn are present in solid solution. Metals like iron which are considerably more noble than Ti can be retained in the anode residue a can interstitial solutes like 02, N2 or C. intermetallic compounds such as TiCrz and TiFe2 are also retained in the anode residue as heretofore set forth.

Having'now described my invention in its in re general aspects, i will illustrate it by examples and in connection with the accompanying drawings, in which Fig. 2 is a vertical elevation, partly in section, of an el ctrolytic apparatus embodying principles of the present invention;

Fig. 3 is a detailed View, partly in section and partly in elevation, of the chlorine-admitting means shown in Fig. 2;

Fig. 4 is a top plan view of the pair of cells shown in Fig. 2; V g

Fig. 5 is a sectional front elevation of a modified cell for use in carrying out the process of the invention;

A Fig. 6 is a sectional side elevation of the cell shown in Fig. '5 and illustrating a mode of discharging product from the cell; and

Fig. 7 is a sectional elevation of a modified form of cell as shown in Figs. 5 and 6, in which the anode and cathode elements are different but in which the organizations for removing plates from the cathode and thence from the 7 cell are essentially the same as shown in Figs. 5 and 6.

In Figs. 2, 3 and 4 is shown an electrolytic cell comprising two similar chambers A and A communicating attheir bottoms through a conduit 5. Since chambers A and A re similar, the structure of one only need be described. v

Chambers A and A are substantially enclosed within a heat-insulated enclosure 7 the interior of which is provided with heating elements e. g. electrical resistance elements), not shown, for maintaining chambers A and A at a desired elevated temperature.

Chamber A comprises an elongated cylindrical pot 8, formed on a scale-and chemically-resistant alloy such as Nichrome V, which pot is provided atits top with an outwardlyeiitending flange 5 and at its bottom with an axially disposed cylindrical sump is of the same alloy. At its top, Pet 8 is closed by means of a water-cooled, gas-L ght, removable cover member 11. At 12 and 13 are shown outer and inner annular spaces, within cover member 11, provided with "communicating inlet and outlet pipes 12a, 12b, 13a, 13b, for circulation of a fluid coolant therethrough.

At 16 is shown an axially disposed titanium anode whichextends for asubstantial distance into pot Saudis electrically insulated from cover member 11 by insulating sleevs 17. The anode is eo'ndu-ctively connected to the positive pole of a direct current source, not shown.

At 29 is shown a split cylindrical cathode which is 29 for use in adding make-up electrolyte to the pot 8 when a desired.

For introducing chlorine into the bottom of pot 8 there is provided an arrangement which is disposed partly in pot 3 and partly in sump it), the same including a silica (quartz) tube 32 provided at its upper end with a funnelshaped mouth having a diameter at least as great as is the a diameter of the cathode 2! which funnel mouth is dis posed beneath the anode 16 and surrounding cathode 20. V

A silica jacket 35 surrounds and is fused to tube 32,

and the upper shoulder of the jacket is provided with a plurality of small orifices 36, 36 for passage of a gas out of the space 37, between tube 32 and jacket 35, into the bottom of pot 3. Adjacent the lower shoulder of jacket 35 there is arranged a valved gas inlet pipe 49 for intr'oducing chlorine, under suitable pressure, into space 37, from a source 41. r

Adjacent its base, sump 19 is provided with an annularly disposed heating means, as indicated at 45, and with a cooling coil, as indicated at 46, for melting and freezing, respectively, the fusible contents of the sump asrequired.

At 47 is indicated a'co'pper bus bar for conducting heavy current between the pots A and A when it is desired to fuse electrolyte within communicating conduit 5.

Example I For the purposes of this example, I use an initial electrolyte of 99% NaCl, 1% 821612, I pass chlorine and current thro ugh the chamber A until a TiCls concentration or 1% of the electrolyte is obtained aed'the open circuit voltage has reached .2 volt. I then transfer the salt from chamber A to the chamber A; the solid product of this preliminary electrolysis may be discarded as it contains any impurities in the salt and is not of the desired physical characteristics. I then carry out an electrolysis in the second chamber -A'. I use in this example-a current density of 250 amperes' per square foot on the cathode. The applied voltage at this current density is 1.0, and the open circuit voltage is ;1-2; Chlotime is added intermittently at orifices 36, 36, to reduce the voltage to .05. The current efiiciency is 20 grams of titanium per faraday.

he cathode deposit IS a solid plate /?3" thick. It shows on analysis only a trace of alkalinous metal which may be due to included salt. Since this deposit is titanium in a form which is not to my knowledge heretofore known, I will describe it in considerable detail.

The fra mentsef cathode plate, as illustrated in Flg. 1d, are bright with crystalline fracture having a bright fracture surface. The density-of the fragments as determined by specific gravity bottle is 4.1. This is substantially higher than that of heretofore known spongy deposits, forthe most dense of which latter I have :found a density of less than 3. It should be pointed out that we are here referring to deposits as they are removed from the electrolyte without washing or mechanical greases plate of my invention shows that it is made up of equiaxed crystals. This is in sharp contrast to spongy or particulate deposits of the known art which are made up of discrete crystals or filiform particles.

Example 11 In this example I set up an electrolytic cell in which I place an electrolyte of 50% NaCl, 43% KCl and 5% BaClz and 2% TiClz. I place a titanium anode in this cell and an iron cathode. The iron cathode is arranged so that it is slowly moved up and down in the cell. I now pass chlorine into the upper part of the cell so that the titanium chloride in this section is partially converted to TiCls. When the cathode is in the lower part of the cell a plate of barium-titanium alloy is deposited; as this moves into the upper part of the cell the barium is replaced by titanium, thus providing a titanium plate substantially free from barium. This operation is repeated until the desired thickness of plate is obtained. When the desired thickness of plate has been formed on the cathode it is lifted from the cell and allowed to drain from electrolyte in an inert atmosphere. The plate is then stripped from the cathode. The product, illustrated in Fig. 1b, is solid plates of tabular habit up to A inch thick of coherent texture and having a density of 4.0. The analysis of these plates is 99.9% titanium.

Example III I proceed as in Example I except that I add chlorine at a lower rate and continuously. I maintain the open circuit cell voltage at 0.2 volt. In this way I obtain plates which contain 0.1% barium.

Example IV In this example I set up a cell as in Example I except that I use insoluble anode of graphite. I also use a cathode of graphite. The initial electrolyte is MgClz with 2% TiCl2. I add TiClz to the cell to maintain this concentration. To provide the necessary conditions for plating I add TiCl4 through a porous graphite element placed just below but not in contact with the cathode. I add the TiCl4 intermittently. The current densities at the cathode and anode in this cell are 100 amps/sq. it. When the cell is placed in operation the open circuit voltage reaches 0.2 volt in minutes. I then add TiCl4 at such a rate that the open circuit voltage is reduced to .05 volt in 10 minutes. This cycle of adding and withholding TiCL; is continued for 10 hours. When the cathode is lifted and drained tabular plates are separated from it which are A" thick. The density of the plates is 4.0.

. Example V In this example I proceed as in Example I except that I use an electrolyte of lithium chloride 98%, SrClz 2%. In the operation of the cell I maintain a steady addition of chlorine which permits the open circuit voltage of the'cell'to-rise to 0.2 volt. I interrupt the current every 'l 5-minutes until the open circuit voltage falls to .05 volt. 1

l 'It should be pointed out that in this and other examples where titanium anodes are used there is a refining action whereby the plates of my invention are pure.

' Example VI I-proceed as in Example I but do not reduce the chlorine intermittently. As a result the plates, illustrated in Fig. 1c, of my invention are formed in rhythmic bands. Intermediate between these bands is crystalline particulate titanium. The reason for this is the same as that for rhythmic precipitaton in gels, the so called Liesegang phenomenon, namely, the conditions for plate formation are enough TiClz and BaClz in the cathode layer to deposit an alloy of Ba and Ti. If Clz is added to remove Ba as deposited, the concentration of TiCl2 will build up in the cathode film and in accordance with the 6 mechanism explained in my co-pending application alkalinous metal will move away from the cathode forming particulate metal. This will then reduce the concentration of TiClz and the conditions for plate formation will be reestablished after a time.

Example VII In this example I proceed as in Example II except that instead of removing the cathode cooling and subs..- quently removing the plates, I place a doctor blade near the top of the cell and cause it to scrape the plate from the cathode as it is moved. The plates of my invention, illustrated in Fig. 1e, are soft and ductile at the temperature of electrolysis and curl up as they are scraped off. They are thereby made to fall into a trough from which they are removed from the cell and cooled in an inert atmosphere.

The cell for carrying out the process is accordance with Example VII is illustrated in Figures 5 and 6. In these figures, 51 is a ceramic-lined cell, provided with cover means 52 and sump means 53. An argon inlet pipe 54a and argon outlet pipe 54b communicate with the interior of the cell. A massive titanium anode 55 extends into cell 51, being electrically insulated from cover means 52 by a suitable insulating sleeve member 56.

At opposite sides of anode 55 there are disposed iron plate cathodes 53 and 59, the same being supported in position by reciprocatable supporting members and 61 which extend through cover means 52 by way of gas locks 64 and 65, respectively. Exteriorly of the cell, there are provided means 67, 5%, for elevating and lowering plate cathodes 58 and 59 respectively for affording the above alluded-to vertical movement of the cathode.

Substantially parallel troughs 70, 71 extend from side to side through cell 51, each being adjacent to a surface of a cathode, and scraper means '72, '73 likewise extend from side to side through the cell, being disposed above troughs 7d, 71, and with their scraping edges in contact with surfaces of said cathodes, for scraping plates from the cathodes into the troughs. For removing the product from the troughs and the cell itself, the latter is provided, adjacent a side wall, with a gas-tight receiver '75 which communicates with ends of troughs 70, 71 by way of apertures through the side wall of the cell, one such aperture being indicated at 7 6, Fig. 6. 77 is a sloping support member extending from beneath the ends of troughs 761. 71 into receiver 7:3, which support member cooperates with a first gas barrier 78 and a second gas barrier 79 to provide a gas lock space 80 in operative relationship to the ends of troughs 70, 71 and to the space 81 within receiver 75 Pushing members 82 are provided for moving dislodged plates from the troughs into gas lock space 30 and thence into space 81. Receiver 75 is provided at its bottom with a suitable discharge means 85 for removing plates therefrom. For maintaining a desired atmosphere within space 81, the receiver is provided witl suitable gas inlet and gas outlet means 37, SS; 1

Sump 53 may be emptied through conduit 90, which latter is provided with heating means 91 and cooling means 92 for fusing or freezing the contents of conduit 90.

In diagrammatic Figure 7 is shown another convenient form of apparatus for carrying out my invention in 'accordance with this example- In this example I use impure titanium in the form of scrap fragments or pelletspro duced from ore in accordance with my co-pending appli cation Serial No. 408,310 filed February 4, 1954.

In Fig. 7, 101 is the stainless steel pot of the electrolytic cell and 102. is its cover. Maintenance of an argon atmosphere within the cell is effected by means of inlet 1423 and outlet L'M. The pot 101 is provided, centrally of its bottom, with sump means 110, 111 is a sump conduit for use in emptying the sump (and, if desired-the pot. itself), the same being associated with heating mean-'3 contents thereof.

Centrally arranged for rotation within pot tilt is a horizontally disposed cylindrical and rotatable. steel cathode member indicated at 115. For removing plates of electro-dcposited titanium from the cathode surface and from the cell interior, there is provided an arrangement (not shown in Fig. 7) including a scraper, a trough, a gas lock and a cooling receptacle similar to that shown in Figs. 5 and 6.

Beneath and spaced from the rotatabie cathode massive graphite anode 113 of unique form. The upper face of anode 113 is'formed as an inverted cone, substantially the whole of the upper surface of which is provided with a series of horizontal relatively deep corrugations 12%, 12:); the function of which latter is to support and retain scrap fragments or pellets of titanium on the sloping surface. The cathode and anode are so disposed with reference to each other that a minor portion of the peripheral surface of the cathode extends into the conical cavity within the upper face of the anode. Conductive elements 122., 122 are accommodated in borings E23, 123 within anode 118 for leading direct current to the anode. At the apex of the conical depression in the face of anode 113 is a central slot or boring 126 which extends through the anode and communicates with sump means L19. Disposed within the upper end of slot 126 is a gaspermeable graphite grid member 139 which is attached to and forms the outlet of a gas conduit 131 which latter communicates between the apex of the conical depression within anode 1&3 and an outside source (not shown) of chlorine or chlorine-containing gas. Grid member 130 is as long as the peripheral surface of cathode 115 is wide.

This cell is arranged'to have fragments'or pellets of unrefined titanium fed into the anode cavity during operation of the cell. This arrangement includes a pair of similar feeding chambers C and C' which are inclined from the horizontal sufiiciently to promote the sliding of solid fragments or pellets over their inclined bottoms 135, 13$ and into the conical cavity in the up er face of anode The chambers are provided with a first barrier 136, 136', and a second barrier 137, 137' to provide, therebetween, a gas lock whereby fragments or pellets may be fed to the anode without admitting air to the interior of the cell and without substantial wastage of the cells atmosphere.

In carrying out the process using the apparatus shown in Fig. 7, atmosphere of argon is established and maintained within the cell by a flow of argon through inlet 103 and outlet 1134. The anode cavity is filled with an electrolyte consisting of a mixture of anhydrous and oxygen-free magnesium and sodium chlorides containing a small amount of added barium chloride, and the -ternperatnre of the cell interior is rm'sed, by conventional heating means not shown) to above 500 C. Fragments of unrefined (i. e. scrap) titanium are fed through feeding chambers C and C into the conical cavity of the anode, the cathode is caused to rotate, and unidirectional direct current is passed through the electrolyte from the to the cathote, current density of 0G amperes per square foot of immersed. area of cathode surface.

The cathode is rotated at such speed as to provide a deposit of solid plate, 1 inch thick, on the cathode surface. To produce this plate, I add chlorine through grid member 134 at a steady rate, and interrupt the current so 'as to cause the open circuit voltage of the cell to vary from 0.1 volt down to .01 volt. The temperature of operation is maintained Within the range 500-900 C.

If the titanium to be refined contains an element form- February 1953. HI operate-above the eutectoid tempe r h imp r e n ad qfbs ag .di sflr retes ed s inte m l c o po nds n h s d 'ji'r id u" r 991 n ted in e mode wil qwi comm t n The eta solid solution formed at high temperatures belowthe eutectoid composition requires greater care incontrolling open circuit voltage to assure complete refining. In certain instances I prefer to .usethis prgccdure and apparatus to produce a plate containing magn'e 'u'gi, barium or strontium. If I use an electrolyte conta ning BaClz, the plate as formed contains barium; 10WYL llf allowing the open circuit voltage on chlorine addition to fall to .Ol volt the barium is substantial removed from the plate. If I operate the cycle between 0.1 and 0,2,vglt, the plates will contain about .5,% barium. If I' add strontium chloride to the electrolyte instead of barium, the plate will contain 0.5% strontium. Magnesiu m .Y be introduced into the plate to the extent f 1.5% using pure MgClz as electrolyte and allowing the voltage to rise to 0.4 before reducing to .05; volt by reducing or stopping the current.

It must be pointed out here that the refining process at the anode depends on the open circuit v ltage. lf the open circuit voltage rises above .18 volt, chromium, if present, will be dissolved from the anode and enter the plate. Iron will be dissolved if the Q. C. voltage rises to about 0.4 volt so that these factors must be taken into account when using my process to produce plates containing magnesium, barium and strontium.

This discussion shows that my process can be used to produce alloys as solid plate, and I wish to include such plate within the scope of my invention. 1 illustrate in the following example:

ample V11 1 this mp I pr c e a is t P ec d -ens cept that it is my purpose to produce solid, plates of titanium alloys suitable for direct melting, and I agcordr ingly use an anode containing titanium and the desired alloying metal. I am able to do this by causing the open circuit voltage of the cell to rise to higher values than when I Wish to ne D in the e Q- C..- a e PP QSL the y n le t are dis vedfrsm th dl d an alloy of, for example, Ba is plated. The d ssolved metal now replaces the barium in the plate on the low current p r of e y le h P Qi E. a pla e o an alloy of the desired metal but only a trace of barium.- The O. C. voltage necessary to dissolve and transport the all y emen s hen p esent i s l d S t n i about as follows:

Eutectoid Volts Temp.

Chromium H 18; i675 Manganese. 04 55b Aluminum. 03 None Iron {J 5 520 In making the alloy plates I operate above the eutectoid temperature and with the open circuit voltage of the .cell at all times above voltage given in the above-table. This table applies only to binary alloys of the metals and if the anode contains non-metals, the voltage for solution may be substantially raised. This is true particularly in the case of aluminum which for refining from a pure binary alloy requires a very low"O. C. -voltage of the cell since it does not form an eutectoidal system .with ititanium, but is 'solublein the alpha phase. However, when oxygen is present I have found that the-aluminumditfuses with the oxygen into the residual anode and .does :not enter the electrolyte as aluminum chloride, but is found as a ternary oxide phase in the anode residue. "With-the other metals listed no interference with the formation bf alloys is caused by the presence of oxygenin the'anode.

The oxygen is concentrated in the residualgnpdfi and eventually enters the anode residue as TiOz.

9 Example IX In this example I proceed as in Example I except that the apparatus is modified by substituting a graphite unit for the quartz unit shown in Fig. 2. In starting the operation chlorine is added exactly as in Example 111. After building up a concentration of 2-3% titanium dichloride in the electrolyte, the anodic current is split between the titanium anode and the graphite, the current in the two anode circuits being so adjusted that one-fourth passes through the graphite. This results in chlorine being passed over the cathode and preferentially combining with the alkali metal, thus maintaining the reduction reaction adjacent the cathode.

In carrying out this embodiment, the voltage drop between the titanium and the cathode is maintained at very nearly zero, whilst the voltage drop from graphite to cathode is about 1.7 volts. In order to maintain the desired current division, a multi-element rectifier is employed, with one end terminal being connected to the cathode and the other end terminal being connected to the graphite, and an adjustable tap, on the rectifier elements intermediate the end elements or terminals and connected to the titanium anode maintains the desired current division.

Example X In this example I used a cell provided with a foraminous potential divider as fully described in my copending application Serial No. 407,610, filed November 23, 1954.

In the present example the electrolyte was composed of 96% NaCl, 2% BaClz and 2% TiClz.

The potential divider was an iron screen of about 3 meshes per linear inch, and was connected to the anode through a .01 ohm resistance. The impressed voltage was 1.0 and the current density 500 amp/sq. ft. on the anode and 50 amp/sq. ft. on the cathode. The anode was an alloy of titanium with 2.5% Cr and 1.25% Fe. The cathode was iron and was the wall of the cell.

After hours operation at 50 amperes I cooled the cell and removed the salt and the deposit. I dissolved the salt in water and obtained a mixture of plate fragments deposited on the cathode and particulate metal distributed in the bath. I screened the recovered metal on a 16 mesh screen, and obtained a coarse fraction of 10 490 grams consisting of plate fragments and a fine fraction of grams consisting largely of particulate metal.

I found on analysis that the coarse fraction contained less than 01% iron or chromium, while the fine fraction contained 10% chromium and 5% iron.

i claim:

1. As an article of manufacture solid plates, uncontaminated by any material on which they were formed, more than .01 inch thick of a virgin metal selected from the group consisting of titanium and zirconium having tabular habit, coherent texture and a density of more than 4.0 in the case of titanium and more than 7.0 in the case of zirconium, said plates being an integral association of tablets in a planar structure.

2. As an article of manufacture solid plates, uncontaminated by any material on which they were formed, of a virgin metallic substance consisting of at least one metal selected from the group consisting of titanium and zirconium alloyed with up to 1% of a metal selected from the group barium, strontium and magnesium, said plates being an integral association of tablets in a planar structure.

3. As an article of manufacture an aggregate of (1) plates, uncontaminated by any material on which they were formed, of tabular habit of a virgin metal having coherent texture, said plates being an integral association of tablets in a planar structure, and (2) non-consolidated crystals of the same metal consisting of a metal selected from the group consisting of titanium and zirconium.

References Cited in the file of this patent UNITED STATES PATENTS 1,552,938 McCord Sept. 8, 1925 2,335,776 Macan Nov. 30, 1943 2,554,031 Jaffee et al. May 22, 1951 2,554,527 Fink May 29, 1951 2,598,777 Frary June 3, 1952 2,705,674 Chubb Apr. 5, 1955 2,734,855 Buck et al. Feb. 14, 1956 2,734,856 Schultz et a1. Feb. 14, 1956 OTHER REFERENCES Chemical and Engineer News, vol. 32, No. 34, Aug. 23, 1954, page 3358. 

1. AS AN ARTICLE OF MANUFACTURE SOLID PLATES, UNCONTAMINATED BY ANY MATERIAL ON WHICH THEY WERE FORMED, MORE THAN .01 INCH THICK OF A VIRGIN METAL SELECTED FROM THE GROUP CONSISTING TITANIUM AND ZIRCONIUM HAVING TABULAR HABIT, COHERENT TEXTURE AND A DENSITY OF MORE THAN 4.0 IN THE CASE OF TITANIUM AND MORE THAN 7.0 IN THE CASE OF ZIRCONIUM, SAID PLATES BEING AN INTEGRAL ASSOCIATION OF TABLETS IN A PLANAR STRUCTURE. 